1. Field of the Invention
The present invention relates to a method of control of playback of motion for controlling the display of an image expressing motion of a virtual being on a game screen and to a program product storing a program and a game system using the same.
2. Description of the Related Art
Recent 3D games etc. include ones which position a virtual being called a xe2x80x9c3D characterxe2x80x9d in a virtual 3D space and generate an image of the field of vision as seen from a predetermined perspective for the display on the screen. For example, in a role playing game, a virtual being called a xe2x80x9cplayer characterxe2x80x9d and one or more other virtual beings called xe2x80x9cenemy charactersxe2x80x9d are sometimes used. Usually, the image expressing a character is comprised of a plurality of polygons corresponding to a plurality of parts expressing the-head, shoulders, limbs, torso, etc. of the character (hereinafter called xe2x80x9carcsxe2x80x9d).
Generation of an image of a character in a game requires use of a set of data expressing the positions and angles of these arcs in each frame. Expression of a series of movements of a character spanning several frames requires use of a series of sets of data corresponding to these frames. This series of movements is called xe2x80x9cmotionxe2x80x9d. The set of data expressing motion is called xe2x80x9cmotion dataxe2x80x9d. Actual game systems store in advance motion data set corresponding to a plurality of movements which a player may desire to have the characters perform.
When desiring to have a character perform one of these movements, the motion data corresponding to that movement is used to continuously change the positions and angles of the arcs of the character and thereby have the movement of the character displayed on the screen. The motion data may be used to display movement of a character in a form close to actual movement. Use of motion data to display on a screen an image expressing movement of a character is called playback of character movement or motion or playback of motion data.
It has been proposed to not only use one set of motion data to express one movement of a character, but to also combine a plurality of sets of motion data to generate an image expressing a desired movement. For example, Japanese Unexamined Patent Publication (Kokai) No. 10-302088 proposes a technique for expressing a rich variety of movement without providing that many sets of motion data. This discloses the technique of combining a plurality of sets of motion data in different forms in accordance with the type of operational input of a player.
Japanese Unexamined Patent Publication (Kokai) No. 11-144084 proposes a technique of expressing smooth movement using a plurality of sets of motion data. This discloses the technique of switching the sets of motion data used for playback along with time so as to use frame images of successively different sets of motion data along with the elapse of time and thereby display movement smoother than when using a single set of motion data.
In conventional games, to give realism to the movement of a character, sometimes movement of the character is switched to other movement in the middle of playback of the movement of the character in accordance with the state of the game. For example, in a role playing game, when having an enemy character try to attack the player character, the enemy character is sometimes conversely attacked by the player character.
In this case, the movement of the enemy character is changed from movement for attack to movement after being attacked, for example, falling to the ground. In these games, movement is changed in this way by switching from motion data being played back to other motion data linked with attack by the player character in advance.
Note that when switching sets of motion data, sometimes a set of motion data before switching and a set of motion data after switching are used for interpolation for a certain period. Interpolation enables the abruptness of the change of the image during switching to be reduced by a certain extent. Switching of the motion being played back is required when the player character is trying to attack an enemy character and conversely when the player character is being attacked by an enemy character.
Summarizing the problems to be solved by the invention, movement of a character after switching is usually determined by the factor triggering the switch, in the present case, the type of the attack from another character. The same is true when a character is continuously attacked in the same way from another character.
In the real world, when one person is attacked in the same way by another person, the movement when attacked can take various forms depending on the extent of the damage caused to the person due to the attack or the cumulative damage sustained by that person. The person will fall to the ground at some times and will stagger back a bit at other times. Similarly, a character in a game is designed to change in condition with each instant along with the progress of the game.
Normally, the condition of a character is controlled by a plurality of types of parameters. For example, these include a parameter expressing the physical strength of the character and a parameter expressing its speed. These parameters linked with a character are updated in accordance with the progress of the game, so the condition of the character is designed to change with each instant.
The inventors thought that to enhance the realism of the game in the same way as the real world, it would be desirable to decide on the motion of a character to be played back in accordance with the condition of the character as it changes with each instant along with the progress of the game such as with one character being continuously attacked by another character.
An object of the present invention is to provide a method of control of playback of motion enabling movement to be performed by a character in a game after being attacked etc. by another character to be determined in accordance with the condition of the character as it changes along with the progress of the game.
Another object of the present invention is to provide a program product storing a program using the method of control of playback of motion.
A still further object of the present invention is to provide a game system using the method of control of playback of motion.
To achieve the above object, according to a first aspect of the present invention, there is provided a method of control of playback of motion comprising determining a motion playback routine from among a plurality of motion playback routines for playing back motion of a character based on motion data, expressing continuous change of an image of a character in a game, in accordance with a value of a parameter linked with the character when an event occurs in the game having an effect on movement being played back of the character in the middle of playing back motion of the character on a screen based on the motion data and playing back motion based on motion data corresponding to the determined motion playback routine in accordance with the motion playback routine after transition from the motion being played back.
Preferably, the plurality of motion playback routines include a plurality of motion playback routines combining motion data defining a motion being played back with other motion data by different synthesis rates and, in determining a motion playback routine, a motion playback routine using a synthesis rate corresponding to the value of the parameter is determined from among the plurality of motion playback routines for combination.
More preferably, the synthesis rate is determined for each of a plurality of pre-established ranges of values able to be taken by the parameter and, in determining a motion playback routine, a motion playback routine is determined which combines motion data by the synthesis rate established corresponding to the one of the plurality of ranges to which the value of the parameter belongs.
Alternatively, preferably, the plurality of motion playback routines include a plurality of motion playback routines for playing back motions based on corresponding motion data stored in advance different from the motion data defining motion being played back.
Alternatively, preferably, the plurality of motion playback routines include a first motion playback routine for playing back motion based on motion data stored in advance different from the motion data defining motion being played back and a second motion playback routine for processing the motion data stored in advance to generate other motion data and playing back other motion based on the generated other motion data.
More preferably, the motion being played back is played back based on motion data stored in advance, and the processing is processing for combining the motion data stored in advance of the motion being played back and at least one other set of motion data.
To achieve the above object, according to a second aspect of the present invention, there is provided a method of control of playback of motion comprising updating a parameter linked with a character in a game in accordance with progress in the game so that the character changes in accordance with cumulative damage sustained from another game element and recovers in accordance with the elapse of time after sustaining the damage and switching motion being played back to one of a plurality of other motions in accordance with the value of the parameter when the character sustains damage from another game element during playback of motion of the character.
Preferably, in switching the motion, when switching to and then playing back one or more motions among the plurality of motions, use is made of motion data stored in advance, different from the motion data defining the motion being played back, as the motion data defining the one or more motions and, when switching to and then playing back another one or more motions among the plurality of motions, the motion data defining the motion being played back and one or more sets of motion data are combined.
Alternatively, preferably, in switching the motion, the motion data defining the motion being played back and another set of motion data are combined by a synthesis rate in accordance with the value of the parameter so as to generate the motion data defining the other motion switched to and then played back.
To achieve the other object, according to a third aspect of the present invention, there is provided a computer readable program product storing a program for a video game to be executed on a computer, wherein the program makes the computer determine a motion playback routine from among a plurality of motion playback routines for playing back motion of a character based on motion data, expressing continuous change of an image of a character in a game, in accordance with a value of a parameter linked with the character when an event occurs in the game having an effect on movement being played back of the character in the middle of playing back motion of the character on a screen based on the motion data and playing back motion based on motion data corresponding to the determined motion playback routine in accordance with the motion playback routine after transition from the motion being played back.
Preferably, the plurality of motion playback routines include a plurality of motion playback routines combining motion data defining a motion being played back with other motion data by different synthesis rates and, in determining a motion playback routine, a motion playback routine using a synthesis rate corresponding to the value of the parameter is determined from among the plurality of motion playback routines for combination.
More preferably, the synthesis rate is determined for each of a plurality of pre-established ranges of values able to be taken by the parameter and, in determining a motion playback routine, a motion playback routine is determined which combines motion data by the synthesis rate established corresponding to the one of the plurality of ranges to which the value of the parameter belongs.
Alternatively, preferably, the plurality of motion playback routines include a plurality of motion playback routines for playing back motions based on corresponding motion data stored in advance different from the motion data defining motion being played back.
Alternatively, preferably, wherein the plurality of motion playback routines include a first motion playback routine for playing back motion based on motion data stored in advance different from the motion data defining motion being played back and a second motion playback routine for processing the motion data stored in advance to generate other motion data and playing back other motion based on the generated other motion data.
More preferably, the motion being played back is played back based on motion data stored in advance and the processing is processing for combining the motion data stored in advance of the motion being played back and at least one other set of motion data.
To achieve the other object, according to a fourth aspect of the present invention, there is provided a computer readable program product storing a program for a video game to be executed on a computer, wherein the program makes the computer update a parameter linked with a character in a game in accordance with progress in the game so that the character changes in accordance with cumulative damage sustained from another game element and recovers in accordance with the elapse of time after sustaining the damage and switch motion being played back to one of a plurality of other motions in accordance with the value of the parameter when the character sustains damage from another game element during playback of motion of the character.
Preferably, in switching the motion, when switching to and then playing back one or more motions among the plurality of motions, use is made of motion data stored in advance, different from the motion data defining the motion being played back, as the motion data defining the one or more motions and when switching to and then playing back another one or more motions among the plurality of motions, the motion data defining the motion being played back and one or more sets of motion data are combined.
Alternatively, preferably, in switching the motion, the motion data defining the motion being played back and another set of motion data are combined by a synthesis rate in accordance with the value of the parameter so as to generate the motion data defining the other motion switched to and then played back.
To solve the still other object, according to a fifth aspect of the present invention, there is provided a game system for playing back motion of a character on a screen based on motion data expressing continuous change of an image of the character, comprising a means for determining a motion playback routine from among a plurality of motion playback routines for playing back motion of a character based on motion data, expressing continuous change of an image of a character in a game, in accordance with a value of a parameter linked with the character when an event occurs in the game having an effect on movement being played back of the character in the middle of playing back motion of the character on a screen based on the motion data and a means for shifting from the motion being played back and playing back motion based on motion data corresponding to the determined motion playback routine in accordance with the motion playback routine.
The present disclosure relates to subject matter contained in Japanese Patent Application No. HEI 11-268449, filed on Sep. 22, 1999, the disclosure of which is expressly incorporated herein by reference in its entirety.